1. Technical Field
The present invention relates to a display device and, more particularly, to a wide band high voltage stabilizing circuit for supplying optimum voltage to a fly back transformer (FBT) according to a change of horizontal frequency or high voltage, by connecting a charge storage unit and switching element to a primary coil of the FBT, the switching element being turned on or off according to a switching signal which a microcomputer recognizing a horizontal synchronization (sync) frequency signal generates corresponding to a frequency band.
2. Related Art
In display devices using a cathode ray tube (CRT), a horizontal deflection current is produced in a horizontal deflection coil to create a magnetic field used to deflect an electron beam (produced by a cathode of the CRT) back and forth across a display screen. As the electron beam is scanned back and forth across the display screen, it is modulated to produce on the display screen spots of varying luminous intensity, thus forming an image to be viewed.
A horizontal deflection circuit is used in display devices using a CRT. Some examples of horizontal deflection circuits are disclosed in U.S. Pat. No. 5,614,794 for Horizontal Deflection Circuit for a Multisync Monitor issued to Yu, U.S. Pat. No. 5,561,354 for Horizontal Deflection issued to Simons et al., U.S. Pat. No. 5,420,484 for Deflection Apparatus for Raster Scanned CRT Displays issued to Morrish, and U.S. Pat. No. 5,469,029 for Deflection Apparatus for Raster Scanned CRT Displays issued to Jackson et al.
In display devices using a CRT, the display can be improved if a stabilization circuit is used. Some examples of stabilization circuits are disclosed in U.S. Pat. No. 5,266,871 for High Voltage Stabilization Circuit for Video Display Apparatus issued to Haferl, U.S. Pat. No. 5,625,261 for Stabilizing Circuit for Stabilizing the Horizontal Picture Size on the Display of a Television Receiver issued to Ogawa, U.S. Pat. No. 5,656,890 for High-Voltage Stabilizer Circuit for a Monitor issued to Park, U.S. Pat. No. 5,317,495 for Stabilized High Voltage Power Supply Circuit issued to Furukawa, and U.S. Pat. No. 5,463,290 for Power Supply Stabilization Circuit with Separate AC/DC Negative Feedback Paths issued to Fitzgerald.
Generally, it is considered desirable for display devices such as cathode ray tubes to include features such as an inexpensive manufacturing cost and an optimum operating capability. Some examples of patents which can help accomplish those features are disclosed in U.S. Pat. No. 3,626,238 for Thyristor Controlled Power Supply Circuits and Deflection Circuitry Associated with a Kinescope issued to Forster, U.S. Pat. No. 3,863,096 for Spot Killer Network for Cathode Ray Tube issued to Sennik, U.S. Pat. No. 3,706,023 for High Voltage Regulation Circuit for Television Receiver issued to Yamada et al., U.S. Pat. No. 5,644,198 for Flyback Transformer Driving Apparatus for Video Display Appliances issued to Park, U.S. Pat. No. 5,691,609 for Power Supply for a Raster Center Controller for a Video Display Appliance issued to Park, U.S. Pat. No. 3,740,571 for High Voltage Dual Isolated Output Tracking Power Supply issued to Richards, Jr. et al., U.S. Pat. No. 3,657,632 for Rectifying Device issued to Miyoshi, U.S. Pat. No. 5,682,083 for Spot Removing Circuit for a CRT with Grid Control Means issued to Shin, U.S. Pat. No. 3,649,901 for High Voltage Hold-Down Circuit issued to Waltner, U.S. Pat. No. 5,650,696 for Method and Apparatus for Protection of EHT and/or Scan Output Stages in Multiscan Displays issued to Krause et al., and U.S. Pat. No. 5,672,939 for Moire Control of a Color Display Device issued to Hsiesh.
I believe that there is a demand to further enhance display devices using cathode ray tubes by providing an improved wide band high voltage stabilizing circuit.